Successful Gene Therapy in the RPGRIP1-deficient Dog: a Large Model of Cone–Rod Dystrophy

Lhériteau, Elsa; Petit, Lolita; Weber, Michel; Meur, Guylène Le; Deschamps, Jack-Yves; Libeau, Lyse; Mendes-Madeira, Alexandra; Guihal, Caroline; François, Achille; Guyon, Richard; Provost, Nathalie; Lemoine, F; Papal, Samantha; El-Amraoui, Aziz; Colle, Marie-Anne; Moullier, Philippe; Rolling, Fabienne

doi:10.1038/mt.2013.232

Cited by 60 publications

(48 citation statements)

References 51 publications

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“…In naturally occurring canine models, both of RPE65-LCA and others, gene therapy has produced similar results: intervention after the onset of photoreceptor degeneration has not been able to modify the natural history of the disease (16) or to restore visual function unless adjunctive treatments are done (40). When the intervention preceded major loss of photoreceptors, prevention of retinal degeneration has often been achieved (16,30,41,42) but not always (17).…”

Section: Discussionmentioning

confidence: 99%

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Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease

Beltran

Cideciyan

Iwabe

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Inherited retinal degenerations cause progressive loss of photoreceptor neurons with eventual blindness. Corrective or neuroprotective gene therapies under development could be delivered at a predegeneration stage to prevent the onset of disease, as well as at intermediate-degeneration stages to slow the rate of progression. Most preclinical gene therapy successes to date have been as predegeneration interventions. In many animal models, as well as in human studies, to date, retinal gene therapy administered well after the onset of degeneration was not able to modify the rate of progression even when successfully reversing dysfunction. We evaluated consequences of gene therapy delivered at intermediate stages of disease in a canine model of X-linked retinitis pigmentosa (XLRP) caused by a mutation in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene. Spatiotemporal natural history of disease was defined and therapeutic dose selected based on predegeneration results. Then interventions were timed at earlier and later phases of intermediate-stage disease, and photoreceptor degeneration monitored with noninvasive imaging, electrophysiological function, and visual behavior for more than 2 y. All parameters showed substantial and significant arrest of the progressive time course of disease with treatment, which resulted in long-term improved retinal function and visual behavior compared with control eyes. Histology confirmed that the human RPGR transgene was stably expressed in photoreceptors and associated with improved structural preservation of rods, cones, and ON bipolar cells together with correction of opsin mislocalization. These findings in a clinically relevant large animal model demonstrate the long-term efficacy of RPGR gene augmentation and substantially broaden the therapeutic window for intervention in patients with RPGR-XLRP.

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Section: Discussionmentioning

confidence: 99%

“…1B). Considering the current evidence showing the difficulty to stop retinal degeneration (16,17), it is of paramount importance to assess the efficacy of new therapies in more advanced disease stages.…”

Section: Significancementioning

confidence: 99%

Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease

Beltran

Cideciyan

Iwabe

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…(37, 40, 59, 60) These methods have been invaluable to demonstrate both the early visual impairment,(40, 59) and subsequent vision restoration following corrective gene therapy in several canine models of inherited degeneration. (34, 36, 37, 61) However, they lack precision as they test global visual function that do not evaluate visual acuity, nor test specific retinal regions for functional defects.…”

Section: Discussionmentioning

confidence: 99%

Assessment of visual function and retinal structure following acute light exposure in the light sensitive T4R rhodopsin mutant dog

Iwabe

Ying

Aguirre

et al. 2016

Experimental Eye Research

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The effect of acute exposure to various intensities of white light on visual behavior and retinal structure was evaluated in the T4R RHO dog, a naturally-occurring model of autosomal dominant retinitis pigmentosa due to a mutation in the Rhodopsin gene. A total of 14 dogs (ages: 4–5.5 months) were used in this study: 3 homozygous mutant RHOT4R/T4R, 8 heterozygous mutant RHOT4R/+, and 3 normal wild-type (WT) dogs. Following overnight dark adaptation, the left eyes were acutely exposed to bright white light with a monocular Ganzfeld dome, while the contralateral right eye was shielded. Each of the 3 homozygous (RHOT4R/T4R) mutant dogs had a single unilateral light exposure (LE) to a different (low, moderate, and high) dose of white light (corneal irradiance/illuminance: 0.1 mW/cm2, 170 lux; 0.5 mW/cm2, 820 lux; or 1 mW/cm2, 1590 lux) for 1min. All 8 heterozygous (RHOT4R/+) mutant dogs were exposed once to the same moderate dose of light. The 3 WT dogs had their left eyes exposed 1, 2, or 3 times to the same highest dose of light. Visual function prior to LE and at 2 weeks and 33 weeks after exposure was objectively assessed in the RHOT4R/T4R and WT dogs by using an obstacle-avoidance course. Transit time through the obstacle course was measured under different scotopic to photopic ambient illuminations. Morphological retinal changes were evaluated by non-invasive in vivo cSLO/sdOCT imaging and histology before and at several time-points (2–36 weeks) after light exposure. The analysis of the transit time through the obstacle course showed that no differences were observed in any of mutant or WT dogs at 2 weeks and 33 weeks post LE. The RHOT4R/T4R retina exposed to the lowest dose of white light showed no obvious changes in ONL thickness at 2 weeks, but mild decrease was noted 36 weeks after LE. The RHOT4R/T4R retina that received a moderate dose (showed an obvious decrease in ONL thickness along the superior and temporal meridians at 2 weeks post LE with more severe damage at 36 weeks post LE in all four meridians. The RHOT4R/T4R retina exposed to the high dose showed at 2 weeks after LE extensive ONL damage in all four meridians. This light intensity did not cause any retinal damage in WT dogs even after repeated (up to 3) LE. Analysis of ONL thickness in heterozygous mutant dogs exposed to the moderate dose of light confirmed the increased sensitivity to light damage of the superior/tapetal retina, and the occurrence of an ongoing cell death process several weeks after the acute LE. In conclusion, a short single exposure to a dose of white light that is not retinotoxic in WT dogs causes in the T4R RHO retina an acute loss of ONL in the central to mid peripheral region that keeps progressing over the course of several weeks. However, this severe retinal damage does not affect visual behavior presumably because of islands of surviving photoreceptors found in the area centralis including the newly discovered canine fovea-like area, and the lack of damage to peripheral photoreceptors.

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“…Various treatment strategies in both RP patients and RP animal models include gene therapies [14–17], retinal pigment epithelium (RPE) [18], photoreceptor [19] and stem cell transplantation [20, 21]. In the initial stage of RP, external compounds, such as antioxidants or neurotrophic factors, protect photoreceptors because they are less invasive [22–25].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Matrix Metalloproteinase 9 Enhances Rod Survival in the S334ter-line3 Retinitis Pigmentosa Model

et al. 2016

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Retinitis Pigmentosa (RP) is one of the most common forms of inherited visual loss with the initial degeneration of rod photoreceptors, followed by a progressive cone photoreceptor deterioration. Coinciding with this visual loss, the extracellular matrix (ECM) is reorganized, which alters matrix metalloproteinase (MMP) activity levels. A potential pathological role of MMPs, MMP-9 in particular, involves an excitotoxicity-mediated physiological response. In the current study, we examine the MMP-9 and MMP-2 expression levels in the rhodopsin S334ter-line3 RP rat model and investigate the impact of treatment with SB-3CT, a specific MMP-9 and MMP-2 inhibitor, on rod cell survival was tested. Retinal MMP-9 and MMP-2 expression levels were quantified by immunoblot analysis from S334ter-line3 rats compared to controls. Gelatinolytic activities of MMP-9 and MMP-2 by zymography were examined. The geometry of rod death was further evaluated using Voronoi analysis. Our results revealed that MMP-9 was elevated while MMP-2 was relatively unchanged when S334ter-line 3 retinas were compared to controls. With SB-3CT treatment, we observed gelatinolytic activity of both MMPs was decreased and diminished clustering associated with rod death, in addition to a robust preservation of rod photoreceptors. These results demonstrate that up-regulation of MMP-9 in retinas of S334ter-line3 are associated with rod death. The application of SB-3CT dramatically interferes with mechanisms leading to apoptosis in an MMP-9-dependent manner. Future studies will determine the feasibility of using SB-3CT as a potential therapeutic strategy to slow progression of vision loss in genetic inherited forms of human RP.

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Successful Gene Therapy in the RPGRIP1-deficient Dog: a Large Model of Cone–Rod Dystrophy

Cited by 60 publications

References 51 publications

Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease

Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease

Assessment of visual function and retinal structure following acute light exposure in the light sensitive T4R rhodopsin mutant dog

Inhibition of Matrix Metalloproteinase 9 Enhances Rod Survival in the S334ter-line3 Retinitis Pigmentosa Model

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